I'd like you to explain what the picture of SLR camera is. Please, thank you. I've never had a concept of this.

The frame is not only a description of the size of the photosensitive element.

Differences between photosensitive elements

Quan Huafu digital SLR

Quan Huafu refers to the size of traditional 135 film. The size of the traditional camera film is 35mm, that is, the width of the film (including the punched part), and the photosensitive area of the 35mm film is 36 x 24mm. The CCD (or CMOS photosensitive imaging element) of digital SLR is the same size as 135 film, and it is called "Quan Huafu".

Non-full angle -APS

The 1996 APS system jointly developed by fujifilm, Kodak, Canon, Minolta and Nikon began to appear. APS is the abbreviation of "advanced photography system", which is translated as "APS advanced photography system" in China. On the basis of the original specification 135, APS developers have made thorough improvements, including all-round innovations in cameras, photosensitive materials, printing equipment and related supporting products, greatly reduced the film size, adopted a brand-new smart cassette design, and integrated contemporary digital technology to become a smart film that can record optical information and digital information.

APS is positioned in the amateur consumer market. The frame format is completely different from that of 135 system, and three negative frames (h, c, p) are designed:

The H-shape is the whole frame (30.3× 16.6mm), and the length-width ratio is16: 9;

Type C is at one end of the left and right ends of the whole frame, and the length-width ratio is 3:2(24.9× 16.6mm), which is the same as that of 135 negative;

P mode is called panoramic mode, and the upper and lower sides of the whole picture are blocked one at a time, so the aspect ratio of the picture is 3:1(30.3×10.1mm).

In digital SLR cameras, CCD or CMOS photosensitive devices with specifications less than 135 are often used. Except for Olympus and Canon Quan Huafu's 4/3 systems, they are almost the same size as APS-C film, so people call this size of photosensitive device "APS-C specification".